Forming truing apparatus



. Oc- 2,2. 1940. H. A. slLvl-:N ET AL FSRMING TRUING APPARATUS 2 Shnets-Shet 1 Filed Feb. 14, 1939 .SKI

oct. 22` 1940.

H. A. slLvEN ET A1.. mamme TRUING APPARATUS Filed Feb. 14, 1939 2 Sheets-Sheet 2 FIL-5.3

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Patented Get. 22., 1940 STATES PATENT oFrlc ter, Mass.,

assignors to Norton Company,

Worcester, Mass., a corporation of Massachusetts Application February 14, 1939l Serial No. 256,320

'2Claims.

The invention relates to grinding machines, and more specifically to forming truing apparatus for the shaping of grinding wheels to a specific shape to grind work pieces to the complement of that shape.

One object of the invention is to provide a forming truing apparatus which is readily adjustable. Another object of the invention is to provide a forming truing apparatus including a form bar which is made up in sections whereby several shaped pieces may be used and placed close together or far apart by spacers. Another object ofthe invention is to provide a forming bar which may be used for a great length of time w before it wears out. Another object of the invention is to provide a forming bar in the form of a surface of revolution'whereby it may be indexed to bring new lines of the surface into contact with the follower to avoid the effects of 2@ wear. Another object of the invention is'to provide a forming truing apparatus of long life and great .flexibility of adjustment. Other objects will be in part obvious or in part pointed out hereinafter.

25 The invention accordingly consists in the fea-` tures of construction, combinations of elements and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope ofthe application of which will be 3@ indicated in the following claims.

In the accompanying drawings illustrating one of many possible embodiments of the mechanical features of this invention,

Figure 1 is a front elevation of a grinding ma- 35 chine incorporating the forming truing apparatus of the invention; 4

Figure 2 is a. view, partly in side elevation and partly in vertical axial section, of the forming truing apparatus, the section being taken along Figure 3 is a front elevation of the forming truing apparatus;

Figure 4 is a horizontal sectional view, on an enlarged scale, of the form bar, the section be- 45 ing taken along the line 4- 4 of Figure 3; and

Figure 5 is a hydraulic diagram.-

Figure 1 illustrates in somewhat conventional form a cylindrical grinding machine. The forming truing apparatus of the invention may be apy 5@ plied to many different types of grinding machines (Cl. 125-11) u the forming truing apparatus of the invention. As illustrated in Figure 1, the grinding machine may comprise a base I0 supporting for reciprocation or longitudinal adjustment a carriage Il which supports a table I2 which may be fastened g to the carriage II in various positions of angular adjustment, as is well known"I in the art. Adjustably fastened to the table I2 along ways I3 is a headstock I4 and also a. tailstock I5. The headstock I4 may support a driving motor Iii l@ adapted to rotate a face plate Il through gearing contained in a gear casing I8 and a spindle I9 which is journalled in the headstock I4. Projecting from the face plate Il is a work holding center in line with and opposite a tail center l@ 2l mounted in the tailstock I5. By means of a hand wheel 22 the tail center 2| Vmay be advanced and retracted toward and from the head center 20, through the medium of screw means, not shown but well known. When the Work piece W has been centered in the machine, a lever 22 is used to clamp the tailstock 2| irmly in adjusted position.

For longitudinal adjustment -of the carriage Il there may be provided any suitable device, such 25 as a hand wheel 25 having a pinion gear operating a spur gear 21 which is connected to a pinion gear 28 meshing with a rack 29 fastened to thel under side o1' the carriage II. The forming truing apparatus of the invention is chiefly used 30 where the grinding is done by -the so-called plunge-cut method, which involves no relative traverse between the grinding wheel and the work piece. Such a grinding operation will form the work piece to a complement or conjugate 'of 35 the shaped grinding wheel. The hand wheel 25 is used to position the work piece W in the exact desired longitudinal position with respect to the grinding element in order Ito produce the shaped portion on the work piece in the desired position 4@ axially.

Still referring to Figure 1, we show a pair of grinding wheels 30 and 3i mounted on a single "spindle, not shown, journalled in a. Wheel head 32, the grinding Wheels being rotated by a motor g5 33 and suitable belting in a casing 34 connected to a pulley on the right-hand end of the wheel spindle. We have not shown the wheel spindle and wheel head in any more detail because any conventional drive and support for the grinding 5o Wheel may be used, such being well known in the art. In order that the Wheels 30 and 3| may be ied transversely relative to the work piece W, there is provided a cross feed shaft 35 on which is mounted a ratchet 36 operated by a pawl 3l 5a which is actuated by a cylinder piston hydraulic unit 38. Any other cross feeding mechanism may be substituted for that indicated.

We provide a massive wheel guard 49. wheel -guard 49 is attached to the :wheel head 32 and has a large opening I4| at the top bridged by a plate 42 having a smaller opening 43. Fastened to the wheel guard 49 on the upper side thereof, as is best shown at the left-hand side of Figure 2, is a truing base 45. As shown, this base has an upwardly rising inclined web portion 46, a curved portion 41, a pair of bosses 48, and an upper plate portion 49. Still referring to Figure 2, longitudinally centrally disposed in the bottom part of the curved portion 41 is a pivot pin 59. Pivotally mounted on the base portion by means of this pivot pin 50 is a slideway 5| receiving a cylinder 52. The angular adjustment in a vertical plane of the slideway 5| may be effected by screws 53 whose lower ends engage shelves 54 integrally connected to the slideway 5|.

This adjustment is usually for minutes of arc only and in order to align the axis of the cylinder 52 with the axis of the wheels 30 and 3| more accurately than can be done by machining operations on the various castings; However, the same result can be achieved by adjusting the table l2 on the carriage Il to alike degree so far as results on the work piece are concerned.

The slideway 5| includes dovetailed portions 56 supporting a slide 51 which holds the dressing tool. The slide 51 is of generally hollow construction, as shown in Figure 2, andincludes a hollow cylindrical portion 58 as well as dovetailed portions 59 fitting the dovetailed portions 56.

As indicated in dotted lines in Figure 3, a piston 69 is located in the cylinder 52 and has attached thereto a piston rod 6| fastened to a plate 62 which extends rearwardly from the slide 51.

Referring now to Figure 2, the cylindrical portion 58 removably supports a sleeve 65 having at the upper end and 'on the front thereof a shelf 66 and having opposite the shelf 66 at the rear thereof a boss 61 to which is fastened a follower member 68 by means of a bolt 69. The sleeve 65 is slidable vertically in the cylindrical portion 58 but lost motion is preferably eliminated by means of a split bottom portion 19 of the cylindrical portion 58 controlled by a pull screw 1| and a push screw 12. See Figure 3 wherein the cover plate 14 of Figure 2 is removed. 'Ihe shelf 66 fits between forked portions .15 of a member 16 attached to the upper part of the cylindrical portion 58 which prevents the sleeve 65 from turning in the cylindrical portion 58. The sleeve 65 is urged downwardly to keep the follower 68 in contact with the4 form bar hereinafter de scribed by means of a spring 89 fastened to a screw 8| in the shelf 68 and a screw 82 in a lug 83 projecting from the cylindrical portion 58. Merely by uncoupling the spring 89 and loosening the screw 1|,'the entire unit supported from the sleeve 65 and including the follower 68 may be removed from the machine.

Supported in the upper end of the sleeve 65 is a bearing 99. This bearing is removable but may be i'lrmly locked to the sleeve 65 as it fits within a cylindrical bore thereof including split portions v9| which can be drawn together to clamp the bearing 99. A sleeve 92 is journalled in the bearing 99 and has keyed thereto the hub 93 of a spur gear wheel 94. The hub 93 is mounted on an upper screw threaded portion This 99. Positive downward movement can be effected because the sleeve 92 has a shoulder under the bearing 99, as shown. Angular movement of the spur gear 94 is for the purpose of adjusting the vertical position of the quill 98 in the sleeve 65; the sleeve 65 moves vertically in response to actuation of the follower 68 to generate the desired contour on the work piece. A dressing diamond y|99 is embedded in a nib |9| fitting in a hole in the bottom of the quill 98 and retained therein by means of a screw |92.

For a delicate angular adjustment of the dia.- mond by rotation of the spur gear 94, we provide a knob |95 on the bottom of a shaft |96 located in a vertical bearing |91 which is integral with a plate |68 fastened to the shelf 66. 0n the upper end 'of the shaft |96 is a pinion gear ||9 meshing with the spur gear 94. A spring-pressed detent, not shown, located in a boss enables the operator to feel the adjustment to a given tooth of the pinion gear ||9 or spur gear 94.

In order to effect a dressing of the grinding Wheels 39 and 3| or either of them, the dressing diamond |99 is moved in the general direction ofthe axis thereof by moving the slide 51 in response to movement of the piston 69 in the cylinder 52. As diagrammatically indicated in Figure 5, this may be achieved by a fluid pressure apparatus, such as a pump ||5 connected to a suction pipe H6 drawing fluid out of a tank ||1 and discharging the iiuid into a piping ||8 leading to a four-way valve ||9 which may connect the fluid pressure to a pipe |29 or a pipe |2|, depending upon the setting of the four-way valve H9, the other of these pipes being by the same valve connected to a return pipe |22 to discharge the fluid into the tank ||1, a pressure relief valve |23 being provided to govern the effective pressure of the fluid. The valve ||9 may be manually or automatically controlled and when it is shifted, the slide 51 moves and causes the diamond to dress the grinding wheels`39 and 3|. Although the slide 51 moves rectilineally, the diamond may be given an irregular motion in a vertical plane by a forming bar, now about to be described, acting on the follower 68.

Referring now to Figure 2, attached to the upper plate portion 49 by means of screws |25, are a pair of supports |26 which are also shown, partly in section, in Figure 4. We provide a form bar spindle |21 which has a central axial cylindrical bore with conical countersnk ends as shown in Figure 4. xThe form bar'spindle"|21 likewise has an enlarged head |39 at one end as shown. We provide a vpair of,hol1ow plugs |3| having conical end portions fitting the conical countersunk ends of the bore inthe spindle |21. We provide a central rod |35 which is lthreaded at both ends, and the rod |35, the plugs 3|, and

the spindle |211 are removably held together by means of nuts |36 on the rod |35. The rod |35 has a close fit in the plugs |3| but may have a loose fit in the spindle |21. The plugs |3| fit with a close fit in bores |31 in the supports |26. By means of the nuts |36 the plugs 3| can be pressed into tight engagement with the spindle A l amasar Aand nuts |4|, the screws |40 being in threaded engagement with and passing through the supports |26 and abutting the head |30 and a surface of revolution form bar mounted on the spindle |21.

As shown in Figure 4 we may provide a plurality of form bar members upon the spindle |21. As illustrated we have provided a form bar member |42- and a form bar member |.43 separated by a spacer formbar member |44. The member |42 comprises a conical portion |42a and a cylindrical portion |42b. The form bar ymember |43 comprises a cylindrical portion |43a, a saddleback anticlastic or pseudo-spherical surface of revolution portion-|431), and a conical portion |43c. This spacer |44 is cylindrical. All of the form bar members have a close fit upon the spindle |21 as shown. Preferably we provide set screws |45 in one of the form bar members, i'or example in the portion |42b of the form bar member |42, to hold ythe form bar members upon the spindle |21.

It will now be seen that the entire unit comprising the spindle |21 and all the form bar members andthe plugs |3| may be removed as "a unit from the machine simply by removing the screws |25, or the rod |35 may be removed from the spindle |21 and the form bar consisting of the spindle |21 and form bar members |42, |43 and |44 may be removed and replaced, if desired, with a differently shaped formA bar. Furthermore by loosening the screws the form bar may be rotated to bring a new portion thereof under the follower member 63. Thus after use of the machine for some time there is apt to be a little wear upon the form bar, but this need occasion no concern when using the form bar of the present invention for it may be readily rotated to bring a new unworn part of the form bar under the follower.

Another advantage of the present invention is the fact that two wheels 30 and 3| or any number of wheels, for that matter, may belshaped to predetermined shapes by form bar members, such as the members |42 and |43, and then spaced diderent distances apart which may be compensated for by using dierent sized spacers |44. In this way modifications of the work piece may be achieved with a very small change of the form bar. By providing a form bar built up of sections, a given shape on the grinding wheel or grinding wheels can be quickly generated by sespherical pieces for theform bar which may be .kept in the tool room. v

` For the dressing of the grinding wheels the valve I0 is thrown into the opposite position from which it is found, either manually or mechanically, and this will cause oil to flow into k.the cylinder '52; moving the piston 60 and thereby moving the slide 5l which carries the diamond |00 as described. As the follower 68 moves along the form bar the sleeve 65 is raised and depressed in the cylindrical portion 58 to generate a shape on the grinding wheel or grinding wheels determined by the form bar. A

It will thus be seen that there has been provided by this invention apparatus in which the lecting'various mechanical, cylindrical, pseudovarious objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changesinight be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

We claim:

1'. In apparatus of the class described, a form bar comprising a hollow spindle, a, plurality of form bar members on said spindle, each one having a surface of revolution, a central rod extending through the spindle, and plugs secured to the ends ofthe spindle by the central rod.

2. In apparatus of the class described, a dressing tool, means mounting the dressing tool for movement i'n a given direction, means mounting the dressing tool for movement in a direction transverse to the given direction, a follower controlling the second named movement of the dressing tool as it partakes of the rst named movement, a pair of coaxial grinding wheels spaced apart in an axial direction, a, form bar member positioned to be contacted by said follower having a contour the same as that of one of said grinding wheels, a second form bar member positioned to be contacted by said follower having a contour the same as that of the other of said grinding wheels, means to hold said form bar members together but not in contact with each other, a spacer separating the form bar members by the same distance that the grinding wheels are spaced, and a mounting for the assembly oi the two form bar members the means to hold the two form bar members and the spacer.

HERBERT A. SILVEN.

RAYMOND A. COLE. 

